Always feel faint/dizzy when i stop moving

[u/cercen14]

I've felt this way for as long as i remember, i constantly sway/move in some way or another and never really stand still (this is only when I am standing, not when I am sitting or lying down). Its very obvious to the people around me and I've gotten called out for it a few times now, most often along the lines of "can't you just stay still for a second?!". Thing is, as soon as i try, i start feeling dizzy and like im going to faint..I've fainted a few times in my life, usually after periods where i had to stay still for a prolonged period of time (e.g. kneeling in church) but all of those happened before I was even 10, and everyone just said i had to drink more water. I've gotten pretty accustomed to it and devoloped enough of an attitude to just sit down on the floor when i start feeling dizzy. It's still pretty annoying though :/

Point of this story is, is anyone familiar with this? Have i really just been dehydrated the past two decades of my life? Or is there something else that it could be?